1. Field of the Invention
This invention relates to a pressure-sensitive adhesive tape comprising a fabric base made of thermoplastic yarn, characterized in that the tape can easily be cut by hand in the direction normal to the longer direction i.e., in the lateral direction, and used for binding packages and masking. This invention also relates to processes for preparing such a tape.
2. Description of the Prior Art
An adhesive tape like that described above has been disclosed in Japanese Utility Model Publication No. 30362/1975. This tape comprises a fabric base made of flat thermoplastic yarns, preferably polyalkylene yarns; and one surface of the fabric base is laminated with a film of the same thermoplastic as that of the flat yarns; and the other surface of the fabric base is bonded with pressure-sensitive adhesive. Furthermore, the fabric base is formed so that the lateral tear strength is lower than the longitudinal tear strength. As methods for decreasing the lateral tear strength of the fabric base, the publication discloses a method in which a plastic having a low thermal softening point and low crystallizability is blended in the warp and the warp is deteriorated by heat treatment in the laminating step, a method in which the draw ratio of the warp is made smaller than that of the filling, a method in which number of warp yarns per inch is made fewer than number of filling yarns per inch and a method in which the denier of the warp yarns is made smaller than that of the filling yarns. However, when the lateral tear strength of the tape is lowered by one of said methods so that the tape can be cut by hand, the longitudinal tear strength of the tape simultaneously decreases and therefore, the tape is not usable for applications in which it is required to have greater than a given strength level, as when used for binding packages.